Hi,

its a mysterious ...have this kind of problems with cossie. I had it too... and today my idle on cold engine is jumping from 700 do 1100 rpm again again and again.

I had your problem too...last year. First, is car running correctly? Under full thortle? ( fuel pressure).

This can be a TPS, ECT or MAP. Lambda has nothing to do with this. In this old engine..lambda is not very important for ECU.

Open the web www.bigturbo.co.uk and find table for ECT and check if you have proper value on hot engine from sensor. Same value is from IAT sensor!

You have to check your MAP sensor.... the best thing is try to change it for test. Or you can measure the voltage comming from map sensor on idle! You find values on bigturbo website.

Next, check your vacuum system for leaks. Pipe to the map sensor, pipe to blow off, breather system, pressure regulator.... Is your TURBO gauge on -0,6 on idle?

You can try to adjust the idle....warm up the car (half of temperature gauge). unplug the ISCV (idle control valve) and set the basic idle with screw under the valve at 900-1000rpm (better with your head lights on).

After this...... tell me your result ..or you can send me PM or skype. But dont remember that cossie is neverending story